title: Expression of a putative alfalfa helicase increases tolerance to abiotic stress in Arabidopsis by enhancing the capacities for ROS scavenging and osmotic adjustment.
abstract: Plant helicases are known to be involved in salinity and low-temperature tolerance. However, a functional involvement of helicases in the antioxidative response of plants has not been described. We have isolated a DEAD-box-containing cDNA sequence from Medicago sativa (alfalfa) that is a homolog of the pea DNA helicase 45 (PDH45) and named it M. sativa helicase 1 (MH1). Transient transfection of 35S::MH1-GFP to onion epidermis revealed that MH1 was localized in the nucleus. Expression of MH1 was detected in roots, stems and leaves of alfalfa. Furthermore, real-time PCR analysis revealed that mannitol, NaCl, methyl viologen and abscisic acid induced the expression of MH1. The ectopic expression of MH1 in Arabidopsis improved seed germination and plant growth under drought, salt and oxidative stress. The capacity for osmotic adjustment, superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and proline content were also elevated in the transgenic Arabidopsis plants. Our results suggest that MH1 responds to reactive oxygen species (ROS) and functions in drought and salt stress tolerance by enhancing the capacities for ROS scavenging and osmotic adjustment.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Luo
authors.forename: Yu Bo
authors.initials: YB
authors.lastname: Liu
authors.forename: Yu Xiu
authors.initials: YX
authors.lastname: Dong
authors.forename: Xin-Qi
authors.initials: XQ
authors.lastname: Gao
authors.forename: Xian Sheng
authors.initials: XS
authors.lastname: Zhang
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D003001:Cloning, Molecular; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D000455:Medicago sativa / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D009995:Osmosis / Q000187:drug effects; D010544:Peroxidases / Q000378:metabolism; D010641:Phenotype; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D012965:Sodium Chloride; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D004265:DNA Helicases